I upstreamed something like our change, so now NetSurf should be able to
build with this or upstream.
https://github.com/JuliaLang/utf8proc/commit/70bbed8626e902d8c1e2b8277b0c61efb8a460bb
I suggest we start building against upstream, as they have other improvements since
this fork.

Use relative symlinks that are independent of installation prefix.
Drop superfluous .so.MAJOR.MINOR symlink, which is and should never
be needed in practice. The purpose of shared library symlinks is to
provide libraries for compile-time linking (.so) and for run-time
linking using the SONAME (.so.MAJOR).

Revise the script to directly read fontforge font files, which are
generated in the makefile. This permits overriding the fontforge path
during the build, and executing fontforge in parallel with make -j.
Avoid duplicating download URLs in the script, which ensures that the
script itself works without network access, e.g., when downloading the
data files on a developer machine with network access and executing the
script on a build machine without network access.